Many chemical and biological reactions are used to provide diagnostics or other test functions in the areas of healthcare, industrial test and the like. These diagnostic tests typically involve introducing one or more reagents to a fluid under test (or one another) in a controlled manner, in order to provide accurate detection of one or more parameters of the reaction that takes place. Examples of such diagnostic tests include immunoassays, blood coagulation assays, and the like.
A particular example of a chemical or biological diagnostic test is a micro-sensor based test strip, where a test strip including the micro-sensors may be dipped into a fluid to be tested, or may include a test reaction chamber surrounding the micro-sensors to contain the reagents and fluid to be tested, where the test reaction chamber is filled with the fluid under test and one or more reagents. The test strip reagents may be deposited onto a test strip surface during manufacture, prior to use, which are then activated upon contact with the fluid under test or activate the fluid under test.
In such test strip sensors, it is particularly useful to control the placement of the reagent in relation to the test micro-sensor, such as on the micro-sensor or in close proximity, and in relation to the flow of the biological or chemical sample. Often this placement must be done with high precision (e.g. variance<25 microns).
Where a reagent is deposited during manufacture of the test strip, ready for activation upon contact with the fluid under test or the like, it is advantageous to reduce the number of process steps required to form a test strip, since these test strips can be manufactured in the millions. Moreover, to ensure the consistency of the results, the manufacture of the test strips should be consistent also. This is particularly the case for micro-sensor based test strips, as the tolerances for the reagent deposition can be very tight.